Stylus construction



uNn' o STA This invention relates to a stylus" construction been had to"so -called scratch filters. Such filters,

.. the mechanically generated type.

shock and. abuse.

.ness with substantial vertical compliance.

terms lateral and vertical refer to the normal playing position'with apick-up riding on top of a substantially horizontal fiat record. Thelateral rigidity involves rigidity substantially Patented Dec. 14, 1948:11 I

STYLUS CONS TRI IC'IION IX Benjamin B. Bauer,- Oak Park-"11L, assignor;by"v mesne assignments, to Shure Brothers Incorpo rated, Chicago, 111;,a corporationof Illinois Application October 16, 1945;, a Ndfsstaseforuse in phonographreproducersand picktl'lps- '-The stylus constructionof this invention is par- ;ticularly adapted for use withreproducers'operating on records having a laterally sinuous'soundgroove: I p

In reproducing froin records having such a laterally sinuous soundgroove, there is customarilypresent so-ca lled record noise or scratchThis is generally present in' new records and increases with use. Suchrecord scratch exhibits a continuous or band spectrum over a substantialfrequency range, but'usuallyhas a substantial part of its energy infrequencies above 300d cycles per second. The precise energy spectrumdepends upon the recordmaterial, reproducerand other factors.

In order to eliminate'record noise or scratch in the case of electricalpick-ups, recourse has usually an electrical flow-pass system, operate.upon the pick-up output to eliminate frequenci'es in theso-calledscratch band. Asa rule such filters are adapted-to eliminate-frequencies above about 3500 cycles'per second as a, com- "promisebetween scratch elimination -and fidelity of reproduction.Itisevident that reproduction is impaired' and the higher frequencies;characteristic of individual instruments and voices, are entirely lost;

It has been determined that scratchin-an 'electrical pick-up not only 4involves a anelectrical "scratch output at the pick-up terminals but Ialso includes generation of audible noise-at the region of stylusvibration. Apparently mechan--- .ical vibration incident toreproducer'operation generates noise-which is partly generated", byrecord vibration and partly by stylus and repro- 1ducer vibration andreflected from ;surface. I

,-.-The invention herein provides a stylus 'con- ;struction whichprovides reproduction'from northe record mal sound tracks ina record-butis remarkably free from reproduction of scratch particularly In addition.thereto,the invention provides .a construction which protects therecord against mechanical Ithas long been known that desirablestyluscharacteristics demand substantial lateral stifi-- The 11 Claims. (Cl;274 -38) I -tures have not been 'satisf-actory'for the-"reason that ahigh vertical compliance was inconsistent to a large degree withlat'eral rigidity; The two along a the perpendicular to a'sound track 1.e.

af -lin substantially parallel to a record radius at the stylus tip."Thevertical compliance refers to compliance alo'ng a, vertical linesubstantially perpendicular' 'to the record'at the stylus tip. Thus byhaving lateral stylus rigidity, vibrations generatedat'the stylus tipinfollowing a sound track are faithfully transinitted' tothe-reproducerjproperJ On the other hand, any sudden stylus movementsalong a vertical line-are sub stantially attenuated' -prior to reachingthe re- "producer proper. Gradual stylus movementsto accommodaterecord'unev'enness due to warping for" example are transmitted totherepro- *duce'r proper so-that floating r at a constant styluspressuremay; be effected. v I

"Prior" art constructions "have been undesirable 'ior various reasons.Thus mechanical-simplicity and efficiency are-essential.- Complicatedmechanical structure's usually have a complex responseto' vibrations,particularly when the range of frequencies'is extended. 'f Suchstructures 1 are" difiicult to manufacture in' quantity and tend tochange their response characteristics as parts ageor 'arest'ressed.--The more simple struchave been dependents in prior art structures withthe actualdesign having a' compromise, By virtue of the inventionherein,the mutual dependence of vertical compliance and lateral rigidity hasbeen largely-"eliminated.

The invention achieves the'above withoutsacrificing mechanicalsimplicity. By virtue of the invention, a structure embodying thinvention is'en'dowed with highlydesir'able mechanicalcharacteristics'and greatruggedness. Thus the inprovided. "For verticalstylus vibration, howvention "provides; 'a "structure Within which adelicate interplay of forces maytake place during normal'u'se but whichis protected against shock and rough usage. The resulting'structure thusis capable of substantially scratchless record reever, apath havinggreat compliance is presented.

By virtue of'ithe mechanical structure near the stylus "point, advantageof vertical compliance is 'take'n to endow "the structure with shockpro- ..invention.

.an end. portion .2 l.

tection. In addition, the parts are so shaped and disposed with relationto each other that undesirable moments are efiectively eliminated. It isalso possible to obtain great vertical compliance without utilizingrelatively weak and fragile parts.

In another aspect, the invention generally provides a spring between thestylus tip rand reproducer proper. Between the spring and stylus tip,there is provided shock absorbing means, which function by virtue of thevertical spring compliance. sive vertical loading is efiectivelyprevented.

For a further description wof the invention, reference will now be madeto'the :drawings wherein Figure 1 is an elevation showing the inventionin use in a pick-up. .Figurelis afront elevation partly in section ofthe needle'struc- Side view similar .to .Figure 3 but showing theposition assumed bythe construction when subjected to excessive verticalloading. Figure is a :side elevation of a modified .form of theReferring to Figures 1-4 inclusive, tone arm H] may be provided withasuitable stylus clamping means such as screw II for retaininga stylusinpredetermined fixed position for reproduction.

The tone armand reproducer may be of any desired construction and sincetheyarenot part of the invention will not be shown or described indetail. The reproducer may either be of the mechanical-type or may beapick-up adaptedto translate mechanical -vibrations' directly orindirectly into electrical waves. .As shown, :the stylus consists ofshank l2 havinglflattenedtpor- -tion I3 adapted to be engaged byclampingmeans l I. for firm retention. Shank llmay be made of any suitablematerial such as steel,:alu.minum, or any-- other elastic materialand-asshown here :has a portion thereof shapedto form ailateral stub l5.

.StublE may be downwardly-bent at any desired angle away from the axisofshank lland as shown is bentat anangle somewhat less than -90-degrees. 'Stub l'5 terminates vimknob-or head portionlfi to which may berigidly attachedwa .spring truss generally designated as I1.

Since the shank is generally inclined .as shown, 'adueto .conventiona1reproducer design,:.and since-it-is desirable to inclinespring'trussl'laway from vertical to utilizeits compliance, the additionof vstub I5 is beneficial.

The structure designated byinumeraldl is an open truss-like structurewhich-mayadvantageously taper in width from a small width at: the.stylus end to a maximum width .at the upper shank end. This is notessential but'does endow the structure with desirable mechanicalproperties. As shown here, truss-like structure 11 is in the form of aspring leaf andmay be fastened to head 16 in any desired manner.Thus'the spring may be suitably .apertured to permit threading on stubl5 and the metal .of head 16 may .be rolled or peaned overto maintainthe same firmly in position. Spring l1.may be made of spring steel,beryllium copper, phosphor bronze or other elastic materialand,.as'shown. in Figure 2, is generally tapering with the "wide portionadjacent head [6. Spring I! has two arms l8and l9 whose ends are rigidlycoupled at head t6 and End portion-2| is shaped-to form agenerallyVspring heelg-having portions Thus damage to record grooves by exces- 22and 23 with a fold section 24 as the V tip. fhe entire V portion is bentdown from truss-like structure I! as seen in Figures 3 and 4. Part 23 ofthe V is provided with a stylus point 25 which 5 may be of any suitablematerial such as steel, carboloy, osmium, a jewel, or the like. Styluspoint 25 may be mounted in part 23 in any desired iashion; :If desiredtlieg heelrzmay simply .be. fastened to spring ITxnear .the lowercendwith the spring extending continuously beyond it. It -.is clear that theheel is rearwardly of the stylus tipas seen from the front of the tonearm.

As evident from Figure 3, V portions 22 and tza-areso disposed withrespect to each other and -5 with-respect to-truss-like structure H thatpoint 25,.particularlyztip 26 thereof, substantially lies .on theprolongation. of the axis of shank l2. Furthermore; the spring structureand stylus tip ..are-so proportioned that tip 26 is substantially in theplane determined by truss-like structure .11.. .In' other .words, it ispreferred to.-so proportion and dispose the various parts ofthestructurebelow. shank-l 2 that the prolongation -of=the axis of shank. l2 pwil1vintersect the plane of. truss-like :structur e l'!' substantiallyatthestylus atip. :It is understood that the above relationshipiis true..when the normal loadison thestylus-tip. The truss-like structure isordinarily .bowed as: shown in dottedlinesin Figure 3 whenthe stylusisfree 330 :-Of. all loading. Hence when. normal vertical loadv.ingisapplied, truss-like structure I! becomes straight. T

The .truss-like structure may be for-med of spring wire "with. the endsrigidly coupled to .the

;, .shankandend portion 21. .If desired, asolid leaf .spring may .be:used.

It is clear that lateral rigidity will bepresent ,solongasthe arms donot buckle under com- ..pressive-forces. In order to provide additional.340 support to-the truss-likestructure itis preferred todispose a .pad20 betweentheearms. This pad ispreferably of material likeViscoloidfrubber, .-leather or the liken-having.substantial vibrationdamping properties. -While the pad .shape may 5 vary, itis preferredto-provide-"a pad filling .the ..entire open space between the arms.Theqpad may beiorced into position and since itis thicker thanthetruss-like structure, it will 'rretain itself in. place. I Preferablypad 20 extends not only'zthe full length of truss-like structureul'lnbutbridges ..the .V heelporticn to abut against stylus tip'25. Thus pad 20-tends to stiffen the entire structure and ,provideszdamping .in bothlateral and vertical "directions.

Vertical damping is clearlydesirable andtends .to suppress scratchvibrations. LateraL-damping ..is so designed .as todmprove the'vibrationtransmission characteristics'of the truss-"like structure andflatten out: any resonance peaks "which may 50 be present. The dampingin two planesten'dsto ..suppress any complex modes of'vibration ..and..restricts the. truss to simplemodes oflvibration "in.lateral-andvertical directions. I

The entire stylus constructionrmay be mounted in any desiredfmanner.However; for ease of manipulation in setting the pick-up in playingposiition andiease ofitracking, it is'preferred to dispose the stylusconstruction as shown. *Thus the'plane generally: determined'by'truss-like structure I! HIOmay .be:.inclined to the record to forman acute angle in the" direction of record travel. It is pre- 1 ferredto'have thegeneral plane'of the truss-like structure intersectitherecord in a line. generally .paral1el:to:a line passing through thestylus point and -;.perpendicular to t the sound --track. Then tiomcomponents. The various; parts i are/ so pros-'- Iiortioned: anddisposedszthatstylus i'tipi 26,;under' normalrplay-ing conditions,=. issubstantially :collin ear :withthershank: axis andin-the generaLplane;

of; truss-like: structure- H; This collinear relationship-isofsubstantial importance Thus lat:

eralrstyluswtipvrnovements create shank bending; movements;- This istheudesiredmodexofi op.er--t azticn ,No torsional moments on the shank:are: created since the force on the stylus: tipg'is-ap-e plied. on; the:shank axis.- 1 The; reproducerdoes which .-it iisnnot normally designed?torreceiver,

tures sthe'resilient portions. have been; comparae tively short.Tl'ius-unless-weak springswere used;- compliance was low, 'Any-increasein spring;

len-gth. would, generally-interfere with proper.

pick.- up.- operation. I-Iere however, the-length of:

truss-like structure I1 is independent-of proper: piclr u-pa operation.general-plane of the truss-like structureqintersect at thetstylus tip,length of-vthe truss-likestructure.

will not affect transmission of later; stylus vibrae' tions. However,along trusslike structure per-- mits greater compliance for undesired.vertical vibrations Without using objectionablythin truss material.

In normaL foperation; components;normally tendingrtol'generate recordscratch and vibrate the. stylus-tip generally vertically to the recordwilLbeattonuated because ofyertical flexibility ofltru'ss' 1.11. Ontheother hand; lateral reproducing stylusmovements will be transmitted bythe lateral rigidityof the trussrlike structure to. the shankproper. f V

"The .r heel structure asnparts 22 and: 23 so dimensioned with regard tophysical'leng'th, lw'idtl'rv and thickness .thatunder norm-a1 playingcondi-w tions', such as shown in Figure 3, fold 24lisi disposed ,a shortdistance above record 212111 the rearof the stylus tip. Fold 24 isproferably curved sonofedge will'znar therecord'. Thus, i'f'the stylus,Happens: to he overloaded) as during dropping;v

Since the .shank axis; and

, connection. with Figure: 4..

' Referringimow toffiig'urefieaamodifiedistructure iSi-ShOWHr whereinthe pickeup generally? is WIDE- 1 videdtwith,,astorsionrrodv1|lkwhoseaxis isrgenerailyu parallel-twine:plane' ofrrecord 211.;Arraexamplez on. a'zpiclwip ofethis character: isidisclosed ;invPa-t-I'ent;- 2',-326;280r.v issued x. August 10-, 1943. Torsion. rocl 3flemayehavevas suitable: clamping. screw 31:2 extending in-ton thesameefrom; the. bottomvfac ,w Clamping screwi- 3il 'rigidly maintains;a: springs: truss structure: or the same.- general-constructiomassshownt i-li'li Figurese 12-4: inclusive 'lihee truss? like structure:mayw bee retained l place by .a;' clamping, endlportionw32 engaged byscrew 35'! In thisimodifiedi construction stylusf tip 2-6 is l normal-lye in the: genera-l1; plane of; spring trussslilreq ru u e;- e l Y Itis clear;- that-ether stylus: construction: acts-in: precisely the samemannerassimFigures, elusive; In thel-preceding figures the: alignmentof.-sty;lus=.-tip;and shank axisprevented. the-genera ation oftorsional:moments-onltheshanks. Hence& the shank wastgenerailyt'subi(acted. to; transverse momentst-tending'tc; bend. it-.. Itse-stifinessis-amples to transmit-such bending, momentseto the; reprcv ducenproper-h In the; construction; ofhFiguretr.5

the-Jshankris entirlywliiriinated. Howevervthe:

forcestrfromt the. truss-alike structure: are "in; the;

same direction as in thelpreviousconstruction.

In. the eyentrthat truss-like structure I! ;is replacediby alsolidhiiatspring it-.issclear:thatlthe parts. vszi l l, liave..tolloeeproperly proportioned to obtain-- the; shock-absorbing}: action.des.cribed--. in v In such case; the-- spring rnayn be, elongated; topromote flexibility; Byvirtue. .of thei invention ahighly desirable;

; stylusconstruction-As:provided. In use; thereon-5 structionA-protectsbothethe'usuall-y fragile stylus? tip; and ffinetrecord 2 grooves;against seriousflam age I .1 Thee usual scratches; across. a: number;or} record ,grooves; resulting; from: careless handling: willrbe,generally; eliminated; Im addition: to all; this, reproduction; iseffected .-at substantially no; reduction-inseificiency: r

,While: the stylus construction :=has beemzdisl-u closedias genera-11y)"inclined in: the: dii-YBCtlQIIL'OfA and moved across, record I groovesat the saine time; ia smooth surface will slide over the recordand"noidarnagetosound grooves willb-e possible." The'el'asticity'oftheftruss material together with the" dimensioning of thejvarious"portions fof" the truss-like" structure "and dissipation insert are suchas to provide a'shocl; absorbingaction; [Ihus i'rrtl'ie eventofexcessiveyertical' loading as when theenti 're' pick-up structure is; droppedonfstylusi 25;fiexureof truss-like" structure"l1 will result.

' It is evident that the entire truss like'structure' willbe flexed"inthe 'manner shown in; Figure 4; ilfer to bow the truss -like structuregenerallyt'o wardt'he record: The insert of dissipationmaterial has"sumcient: flexibility so itwilljbend also. 'Ilrllisfiexure of" thetruss-likestructure will dopress'fold 24 so that it engagesrecord Z'Ior' what.-

ever is hit; Stylus 25 willbe swungupwardly to clear record Bypropoitioningthew length of: trusslilie s'trlu'cture' ll," therelatiyewidth of van-- reversed if so desired; v

,What-:iszclaimedzisr w 1: Inc: a: phonograph reproducen: having"; ar'vibrata'ble; membenz-a; stylusaconstructiorr in ch'idinga lgenerallyfiair's'pring;:morma'lly extending; from: said:reproducendownwardlytoward: a; record, said spring. having: it'smppen" end: coupledf to saidvi recordrtravelgflit is: clearrthatz therst'yhzls smay; bee

. bratablexmember:saiditspringrhaving atiits lower ous portions of 'thetruss like structure and (16- 1: I

signing: the proper insert, it ispossibleto obtainz the action shown inFigure- 4. This 36131011 15; important-since; it protects the: stylustip .from breakage vand also protects the delicate rec0rd groovesfrom-being damaged in case thei'repro- 1 4168 made-travels; acrosssoundtracks;

endaaigenerally v shapled heel pcrtiorr normally: extending. downwardlytoward; said: record but= clearing-r'the :same in; normal?- playi'rrgpc'siti'orfi a stylus tip carried by the free end of said v-andf havingnormal:engagementrwitlra soundQ-trackin same-record; said 'v having thearm's thereof rela tivelyf' rig-ids said spring: generall'y'd-eterminin'g a plane: intersectingthe=--re'cord along ar lineg'enerallwperpendicularrtcr thersounditrack sat 'thes'tylus; tip;saidiaspringz Being: flexibl'ez along lines per pendioiflanitoathegeneral spring plane and 'b'ei'ng rigid along flineszlyingrwithin thespring plane," saidf'spring being'iadaptedi to. yieldrupon' excessive:vertical:loadingeitosmovesaidfheel into record en gagem-ent: andr clearit'l'IEiStYlllSiifIOHlZ-Sflifh record. 12h 'llhestructure-ofrclaim.Lwhereimsaids'prdng: has am interior: open:'regiorr"extending-longitudinellyrther'eof:andiwherein awibration dissipationmateriatiisr'disposezriwithimsaid'ire'giorr ancr 'ex' 3. Asstylus"construction for use Witha phonograph reproducercomprising a rigid shankadapted to be gripped in a reproducer and during normal operationpointing generally downwardly from'said reproducer toward a record, agenerally fiat spring rigidly carried by said shank and extending towardsaid record, a stylus tipcarried by the lower end of said spring forengagement with a sound track in said record, said spring generallydetermining a plane free of the shank center lineand intersecting therecord along aline generally perpendi'cular'to the sound track at thestylus tip, said spring being flexible along lines perpendicular to thegeneral spring plane and being rigid along lines lying with the springplane, said stylus 1 tip being disposed substantially at theintersection of the shank longitudinal center line and the general planeof said spring.

4. The structure of claim 3 wherein a generally V-shaped heel portion isdisposed between the lower end of said spring and said stylus tip, saidV having the arms thereof relatively rigid, said heel portion extendingdownwardly toward the record and adapted to engage the same only uponexcessive vertical-loading on the stylus tending to flex said springexcessively whereby upon engagement of said heel with said record saidstylus tip is cleared from said record.

5. A phonograph stylus construction including a stylus tip for engaginga record groove during normal reproduction, said stylus constructioncomprising a rigid shank to be gripped in a reprducer and during normaloperation positionedso that its longitudinal axis is inclined in thedirection of record travel at an acute angle to the record plane, anelongated generally flat leaf spring having one end thereof rigidlycarried by said shank and normally extending downwardly toward a recordand inclined in the direction of record travel, said leaf springgenerally determining a plane intersecting the record plane in a linegenerallyparallel to a line perpendicular to the direction of recordtravel at the stylus tip, a stylus tip carried by the free end portionof said leaf spring and normally engaging a record groove, said free endportion having a heel portion extending downwardly toward the recordrearwardly of the stylus tip, said heel portion and stylus tip beingrelatively rigid, said heel portion including a record engaging portionnormally clear of the record, said leaf spring being so inclined withrespect to, the shank axis that the stylus tip is substantially inlinewith said "shank axis, said leaf spring being adapted to yield uponexcessive vertical loading upon. the stylus to move said heel recordengaging portion toengage said-record surface and raise the stylus tipout of normal engagement. r

6. A phonograph stylus construction including a stylus tip for engaginga record groovesduring normal reproduction, said stylus constructioncomprising a rigid shank to be gripped ina reproducer and during normal:operation positioned so that its longitudinal axis is inclined in thedi-- rectionof record travel at an acute angle "to the record plane, anelongated generally flat leaf spring having one end thereof rigidlycarried by said shank and normally extending downwardlytoward a recordand inclined in the'direction of,

recordtravel, said leaf spring generally. determining a planeintersecting the record in a line generally perpendicular to thedirection of record travel at the stylus tip, a stylus tip carried bythefree end portion of said leaf spring and normally engaging a record:groove, said free. end portion- 8 having a heel portion extendingdownwardly toward the record rearwardly of the stylus tip, said heelportion and stylus tip being relatively rigid, said heel portionincluding a curved record engaging portion normally clear of the record,

said leaf spring being so inclined with'respect to the record plane thatexcessive vertical loading upon the stylus will cause downward fiexureof the leaf spring and a downward movement of said heel record engagingportion to engage said recordsurface and raise the stylus tip out ofnormal engagement.

7, A phonograph stylus construction including portion thereof cut out,vibration absorbing material disposed in said -cutout portion, said leafspring generally determining a plane intersecting the record in a linegenerally perpendicular to the direction of record travel at the stylustip, a stylus tip carried by the free end portion of said leaf springand normally engaging a record groove, said stylus tip and leaf springbeing so inclined with respect to the record plane that said stylus tipis substantially coincident with the longitudinal axis of said shank,said stylus tip being normally in the plane determined by said leafspring, the free edge portion of said leaf spring being shaped to form ageneral V with the tip of the V pointing generally downwardly toward therecord and normally being clear of the record, said leaf spring beingadapted to flex under excessive vertical loading so that the tip of theV will engage the record surface and rock the stylus tip clear of therecord.

8. A stylus construction for use with a reproducer, said constructioncomprising a spring member having one end adapted to be coupled to atransducer, 2. heel structure disposed at the other end of said spring,a stylus tip disposed adjacent said heel, said stylustip beingrelatively rigid with respect to said heel, said heel normally clearingthe record surface but being forced down against the record uponexcessive vertical loading of said stylus tip, said heel upon engagementwith said record surface functioning as a pivot so that additionalflexure .of said spring due to excessive loading causes said stylus tipto be swung upwardly from a record.

9. A stylus construction for use with a reproducer, said constructionincluding a spring trusslike structure normally extending from ar-epro-.

ducer downwardly toward a record, said structure having its upper endcoupled to a vibratable mem-.

ber in said reproducer, a heel portion at thelower end of the springstructure and extending downwardly toward the record, a stylus tiprigidly joined to said heel portion, said heel portion being betweensaid spring structure and stylus tip, said truss-like structuregenerally'determining a plane intersecting the record along a linegenerally perpendicular to the sound track atthe stylus tip, saidstructure bein flexible along lines perpendicular to the general planeof the structure and being rigid along lines lying within the generalplane of the structure, said heel portion being 9 normally out ofcontact with said record but upon excessive vertical loading andconsequent yielding of said structure said heel approaches said recordand contacts the same to function as a pivot for I rocking the stylustip up from the record.

10. A stylus construction for use with a phonograph record reproducer,said construction comprising a spring member having one end adapted tobe coupled to a transducer, a heel structure disposed at the other endof said spring member, a stylus tip disposed adjacent said heel, saidstylus tip being relatively rigid with respect to said heel, said heelnormally clearing the record surface but being forced down against therecord upon excessive vertical loading of said stylus tip, said heelupon engagement with said record surface functioning as a pivot so thatadditional flexure of said spring due to excessive loading causessaidstylus tip to be swung upwardly from a record, and vibration dampingmaterial disposed along said spring member.

11. A stylus construction for use with a phonograph record reproducer,said construction comprising a rigid shank adapted to be gripped in areproducer and during normal operation pointing generally downwardlyfrom said reproducer toward a record, the downward end of said shankincluding a lateral extension, a spring member rigidly carried at oneend by said extension and extending toward said record, a heel structuredisposed at the record end of said spring member, a stylus tip disposedadjacent said heel, said stylus being relatively rigid with respect tosaid heel, said heel normally clearing the record surface but beingforced down against the record upon excessive vertical loading of saidstylus tip, said heel upon I engagement with said record surfacefunctioning as a pivot so that additional fiexure of said spring memberdue to excessive loading causes said stylus tip to be swung upwardlyfrom a record.

BENJAMIN B. BAUER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

